Reactor useful for chemical vapor deposition of titanium nitride

• US 6,106,625 A
• Filed: 02/13/1998
• Issued: 08/22/2000
• Est. Priority Date: 12/02/1997
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lei, Lawrence Chung, Johnson, Mark, Chang, Mei, Koai, Keith
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): HASSANZADEH, PARVIZ
• Application Number:
  US09/023,852
• Time in Patent Office: 921 Days
• Field of Search: 118/715, 118/725, 118/723 E, 118/728, 118/500, 118/724
• US Class Current: 118/715
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45572 Cooled nozzles
• CPC Class Codes: C23C 16/4585 Devices at or outside the perimeter of the substrate support, e.g. clamping rings, shrouds
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01J 2237/0206 Extinguishing, preventing or controlling unwanted discharges
• CPC Class Codes: H01J 37/32477 characterised by the means for protecting vessels or internal parts, e.g. coatings
• CPC Class Codes: H01J 37/32522 Temperature
• CPC Class Codes: H01J 37/32834 Exhausting

Abstract

A plasma reaction chamber particularly configured for chemical vapor deposition of titanium nitride with a TDMAT precursor, the deposition including a plasma step. Gas is injected from a gas cavity in a showerhead electrode assembly through a large number of showerhead holes into the processing region over the wafer. The showerhead electrode is capable of being RF energized to create a plasma of a gas in the processing region. The showerhead electrode and other parts of the assembly are cooled by a cooling plate disposed above the gas cavity and connected to a rim of the showerhead electrode. A convolute water-cooling channel is formed in the cooling plate having a small cross section and numerous bends so as to create turbulent flow, thus aiding thermal transfer. The water cooling plate is connected to the showerhead electrode across a large horizontal interface, thus also aiding thermal flow. An edge ring assembly is positioned in a peripheral recess at the top of heater pedestal supporting the wafer next to the processing region. The showerhead is insulated from the chamber body by an isolator having a downwardly sloping lower surface facing the processing region. Thereby, the isolator by itself or in combination with a plasma confinement ring around the wafer confines the plasma to the process area and induces the exhaust to flow downwardly from the processing region. The assembly includes a Z-shaped heat shield disposed between the walls of the recess and of the pedestal side and other parts of the ring assembly with gaps between the various members, thereby promoting thermal isolation in the edge region as well as protecting the side of the pedestal.

Claims

1. An apparatus for chemical vapor deposition, comprising:

a reaction chamber including a pedestal for supporting a substrate, wherein a recess is formed in an upper periphery of said pedestal;

a thermally isolating ring assembly fitted into said recess and including

an edge ring having a generally flat upper surface on a top of said assembly, and

a heat shield disposed between said edge ring and said pedestal and having a first cylindrical portion covering a cylindrical wall of said recess and a ring portion covering a bottom of said recess, gaps being formed between said edge ring and said heat shield and between said heat shield and said pedestal;

a showerhead faceplate member disposed in parallel opposition to and above said pedestal and having a plurality of holes therethrough and a rim extending upwardly of a face of said faceplate and outwardly of said holes, said holes for transporting a processing gas from a gas port within a showerhead assembly including said faceplate member to a processing area adjacent said substrate, said faceplate member being adapted to receive RF power to excite said processing gas into a plasma;

a cooling plate fixed to said faceplate member on a bottom side of said plate and having formed in a top side thereof a convolute channel having inlet and outlet ports disposed in a central portion of said cooling plate for passing a cooling liquid through said convolute channel;

a lid isolator electrically insulating said faceplate member from a sidewall of said chamber; and

a voltage gradient assembly having a proximate end supported on said sidewall and a distal end disposed over said central portion of said cooling plate and including first and second insulating tubes for carrying said cooling liquid and connected at said distal end to said inlet and outlet ports and a third insulating tube for carrying said processing gas and connected at said distal end to said gas port.

2. The apparatus of claim 1, wherein said convolute channel includes at least one U-shaped bend.

3. The apparatus of claim 2, wherein said convolute channel includes at least three U-shaped bends.

4. The apparatus of claim 2, wherein said convolute channel includes portions extending circumferentially of a center of said cooling plate and connecting said U-shaped bends.

5. The apparatus of claim 1, wherein said convolute channel causes said cooling liquid to turbulently flow in said convolute channel.

6. The apparatus of claim 1, wherein said plate is fixed to said faceplate member in an area on top of said lid isolator.

7. The apparatus of claim 6, wherein said plate extends laterally at least as far as said faceplate member.

8. The apparatus of claim 1, wherein a gas cavity is formed on top of said faceplate member and wherein an area of contact between said plate and said faceplate member is at least as great as a lateral area extending from said isolator to said gas cavity less any gap between said faceplate member and said isolator.

9. The apparatus of claim 1, further comprising a cover plate joined to a top of said cooling plate and sealing a top of said convolute channel.

10. An apparatus for chemical vapor deposition, comprising:

a reaction chamber including a showerhead faceplate for supplying processing gas through apertures in said faceplate;

a generally circular pedestal included within said reaction chamber and having a support surface placeable below said faceplate for holding a substrate being coated, a recess being formed in an upper periphery of said pedestal;

a thermally isolating ring assembly fitted into said recess and including

an edge ring having a generally flat upper surface on a top of said assembly, and

a heat shield disposed between said edge ring and said pedestal and having (1) a first cylindrical portion covering a cylindrical wall of said recess and shielding substantially all of said cylindrical wall from said edge ring and (2) a ring portion covering a bottom of said recess and sheilding substantially all of said bottom from said edge ring, gaps being formed between said edge ring and said heat shield and between said heat shield and said pedestal.

11. The apparatus of claim 10, wherein said ring assembly includes a three-point support between said assembly and said pedestal.

12. The apparatus of claim 10, wherein said heat shield includes a second cylindrical portion extending in parallel to a side of said pedestal below said edge ring.

13. The apparatus of claim 10, wherein said edge ring comprises an electrical conductive material and further comprising a bent electrical strap electrically connected to said pedestal and having a point electrical connection to said ring assembly.

14. The apparatus of claim 10, further comprising a ring isolator disposed between said edge ring and said heat shield with gaps therebetween.

15. The apparatus of claim 14, wherein three bushings are extend through said ring isolator and have respective two ends protruding therefrom to form spacers against said edge ring and said heat shield.

16. A processing chamber for forming films on a substrate, comprising:

a chamber body having a chamber cavity extending from a top portion to a bottom portion thereof between walls of said chamber body;

a pedestal movably disposed within said chamber cavity between said top and bottom portions;

a chamber lid assembly supported by said chamber body adjacent said top portion and including an isolator ring member and a showerhead both supported by said isolator ring member, said isolator ring member, said isolator ring member having an isolator ring lip with a sloping surface facing said chamber cavity and extending downwardly and away from said showerhead and a generally planar surface positioned radially inside of said sloping surface, facing said chamber cavity, and lying approximately parallel to a face of said showerhead, an annular pumping channel being formed radially outside of said isolator ring lip; and

a chamber insert assembly supported by said chamber body within said chamber cavity and having a shield member supported on said chamber body and including a shield body and a shield ridge protruding from said shield body towards said isolator ring lip and forming a choke aperture therebetween communicating said chamber cavity with said pumping channel.

17. The processing chamber of claim 16, further comprising an insert member supported on a bottom of said chamber body and supporting said inner shield member.

18. The processing chamber of claim 17, wherein said inner shield member comprises a metal and said insert member comprises a ceramic.

19. The processing chamber of claim 16, wherein said generally planar surface terminates in said sloping surface and lies approximately in a plane of said face of said showerhed.

20. The processing chamber of claim 16, wherein said shield member additionally comprises a shield lip integrally bound to said shield body and supporting said shield ridge in an integral relationship.

21. An edge ring assembly fittable into an recess formed in an upper, outer corner of a pedestal arranged around a vertical axis and used for supporting a substrate in a chemical vapor deposition reactor, comprising:

an annular metallic ring arranged having a planar upper surface and supportable by three point contacts on a lower surface of said recess; and

an annular Z-shaped ceramic heat shield supported on a lower side of said ring and having a first cylindrical portion extending vertically along substantially all of a side of said recess, a horizontal portion connected to said first cylindrical portion and extending horizontally along substantially all of a bottom of said recess, and a second cylindrical portion connected to said horizontal portion and extending vertically along a side of said pedestal radially outside of said recess.

22. The assembly of claim 21, further comprising a ceramic ring supported between said edge ring and said heat shield with respective gaps therebetween.

23. The assembly of claim 21, further comprising a bent electrical strap electrically connectable between said metallic ring and said pedestal.

24. An integral ceramic isolator configured to support a showerhead electrode on and electrically isolate said showerhead electrode from a chamber body in a plasma chemical vapor deposition reactor, said isolator and said showerhead electrode being generally symmetric about a vertical axis, said isolator comprising:

a vertical portion extending vertically from an interior of said reactor at a bottom of said vertical portion toward an exterior of said reactor at a top of said vertical portion;

a first horizontal portion extending radially outwardly from a top of said vertical portion; and

a second horizontal portion extending radially inwardly from a bottom of said vertical portion and having a radially inwardly disposed planar bottom surface and a radially outwardly disposed sloping bottom surface sloping downwardly from said planar bottom surface.

25. The ceramic isolator of claim 24, wherein said sloping bottom surface is curved.

26. The ceramic isolator of claim 24, wherein said sloping bottom surface is extended at an angle downwardly.

27. The ceramic isolator of claim 24, wherein a radially outward wall of said vertical portion is concavely shaped.

28. The ceramic isolator of claim 24, wherein said planar bottom surface is alignable to a showerhead face of said showerhead electrode.